JP2000088811A - Gas analyzing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an indication from being affected by presuure fluctuation inside a piping generated at the time of fluid modulation, even when a magnetic oxygen analyzer is used in combination with a gas analyzer of fluid modulation type. SOLUTION: In this gas analyzing system 1 capable of analyzing gas comprising plural components by combining a magnetic oxygen analyzer D2 with a gas analyzer D1 of fluid modulation type, an output signal Do2 of the oxygen analyzer D2 is held consistently with the timing of the fluid modulation, and a concentration signal processing circuit having a hold circuit H for cutting a noise contained in the output signal Do2 is provided in an output side of the anlyzer D2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to signal processing for a gas analysis system such as a magnetic pressure type oxygen analyzer, and more particularly, to a gas analysis system for removing the influence of pulsation of a sample gas.

[0002]

2. Description of the Related Art Conventionally, when analyzing a multi-component sample gas, a gas analysis system may be formed by combining a plurality of types of gas analyzers each capable of analyzing a unique component.

FIG. 3 is a block diagram showing the configuration of a conventional gas analysis system 2, and shows an example in which the concentrations of carbon dioxide and oxygen are measured. In FIG. 3, D ₁ is an infrared gas analyzer for measuring carbon dioxide, D ₂ is a magnetic pressure type oxygen analyzer, and V ₁ and V ₂ alternately contain zero gas Z or sample gas S in both cells of the infrared gas analyzer D _1. The first and second solenoid valves Vd for supplying to the solenoid valves V ₁ ,
Drive signal Vd1 to operate the V _2, the electromagnetic valve drive circuit for outputting a Vd2, C ₁ ~C ₇ Each analyzer D _1, D
Capillary tubes for supplying sample gas S, zero gas Z, and reference gas R at the flow rates required for ₂ and Ds are concentration signals Do1 and Do output from the analyzers D ₁ and D ₂ , respectively.
2 is a density display section for displaying 2.

The solenoid valve drive circuit Vd has, for example, 1
The solenoid valve V periodically at a speed of about Hz ₁, V_TwoSwitch
Sample gas S and zero gas Z
Analyzer D₁Is to be supplied to In other words, the red in this example
Outside gas analyzer D₁Is a fluid modulation type gas analyzer.
You. Infrared gas as in the gas analysis system 2 having the above configuration
Analyzer D₁And magnetic pressure type oxygen analyzer
The concentration of other components such as carbon dioxide along with the oxygen concentration.
Can be specified.

[0005]

However, the oxygen analyzer D ₂ is a magnetic pressure type oxygen analyzer, which measures an interface pressure difference caused by a measurement gas containing oxygen existing between magnetized magnetic poles. because, a large measurement error alone the pressure of the sample gas S to be supplied to the oxygen analyzer D ₂ varies slightly occurs. Then, as in the conventional example described above, the electromagnetic valve V ₂ to operate when the magnetic pressure oxygen analyzer D ₂ used in conjunction with gas analyzers D ₁ of the fluid modulation scheme, the operation of these solenoid valves V ₂ pressure fluctuations when is transmitted to the oxygen analyzer D ₂ through the pipe. Therefore, in the conventional configuration had appears as an instruction noise effect of the pressure variations during operation of the electromagnetic valve V ₂ is the oxygen analyzer D _2.

Conventionally, in order to prevent causing this instruction noise, longer or the piping between the sample inlet and the capillary C _4, and the like add buffer tank B to the portion of the pipe, the solenoid valve noise generated during the operation of the V ₂ had to be smaller. However, if it is this countermeasure, or cause the response speed difference between the infrared spectrometer D ₁ and the oxygen analyzer D _2, the response delay of the oxygen analyzer D ₂ has occurred.

[0007] The present invention has been made in view of the above points, and even if a magnetic pressure type oxygen analyzer is used in combination with a fluid modulation type gas analyzer, the pressure in the piping generated at the time of fluid modulation can be increased. An object of the present invention is to provide a gas analysis system that prevents the influence of an instruction from being caused by fluctuation.

[0008]

In order to achieve the above object, a gas analysis system according to the present invention is capable of analyzing a gas of a plurality of components by combining a magnetic pressure type oxygen analyzer with a fluid modulation type gas analyzer. In a gas analysis system, a concentration signal processing circuit having a hold circuit that holds an output signal of an oxygen analyzer in accordance with the timing of fluid modulation and cuts noise included in the output signal is provided on the output side of the oxygen analyzer. It is characterized by.

Therefore, when the solenoid valve is switched, the output signal is held and the measurement result is not output, so that the noise generated in the output signal of the magnetic pressure type oxygen analyzer due to the pressure fluctuation due to the fluid modulation is completely removed by the hold circuit. be able to. Also, unlike the conventional case, there is no need to insert a buffer tank into the pipe or lengthen the pipe, so that the output signal of the magnetic pressure type oxygen analyzer does not delay with respect to the output signal of the fluid modulation type gas analyzer, and Output noise can be completely removed. Further, since the circuit configuration is extremely simple, the production cost can be suppressed as much as possible while exhibiting a sufficient effect.

Further, by generating a control signal for the hold circuit using a fluid modulation signal, the control circuit controls the hold circuit only when an electromagnetic valve used for fluid modulation operates to have an influence on the oxygen analyzer. It is very easy to output a signal and hold the output of the oxygen analyzer so that no indicating noise is produced. That is, the state immediately before the occurrence of noise can be accurately held,
The reliability of the output signal can be improved.

[0011]

1 and 2 show an example of a gas analysis system 1 according to the present invention. FIG. 1 is a block diagram showing an entire configuration of the gas analysis system 1, and FIG. 2 shows a change in a signal of each unit. It is a time chart. In FIGS. 1 and 2, members denoted by the same reference numerals as those in FIG. 3 are the same or equivalent members, and thus detailed description thereof will be omitted.

[0012] In FIG. 1, 2, H is the hold circuit for a predetermined period and holds the output signal Do2 magnetic pressure oxygen analyzer D _2, the hold circuit H is able to use various forms, and in any However, it can be formed by an extremely simple circuit including the buffer Hb, the switch Hs, and the capacitor Hc. Further, as shown in FIG. 2 (C), the hold circuit H includes a switching signal Vd1 of the solenoid valve drive circuit Vd.
It is controlled by a pulse signal Vd3 output for a fixed time t from the switching of Vd2, and this pulse signal Vd3 is output from the solenoid valve drive circuit Vd. That is, in addition to the hold circuit H, the solenoid valve drive circuit Vd
Function as a density signal processing circuit.

As shown in FIG. 2A, when the solenoid valves V ₁ and V ₂ used for fluid modulation of the fluid modulation type infrared gas analyzer D ₁ are turned on / off at a speed of about 1 Hz, for example, the pressure of the sample gas S is supplied to the magnetic pressure oxygen analyzer D ₂ at the time of switching varies rapidly. The pressure variation, to give an indication effect on oxygen analyzer D _2,
The density signal output Do2 has a noise N as shown in FIG.
Will be included.

However, the gas analysis system 1 having the above configuration
According to the density signal output Do2 oxygen analyzer D _2, input to the hold circuit H, so in synchronization with the solenoid valve V _1, V ₂ are running hold circuit H, density signal occurring during fluid modulation The noise N of the output Do2 can be reliably held. Therefore, as shown in FIG. 2D, a signal without noise N can be obtained in the output signal Do 'of the hold circuit H.

In particular, in the above-described example, since the control signal of the hold circuit H is the pulse signal Vd3 output from the solenoid valve drive circuit Vd, the density signal output Do2 immediately before the noise N enters can be held, and the density signal output Do2 can be held. This can contribute to shortening the hold time of the signal output Do2. The width t of the pulse signal Vd3, it is a long minimum width than the time t _N occurring noise N is desirable in order to reduce the effects caused by holding the density signal output Do2 .

By outputting the control signal of the hold circuit H from the solenoid valve drive circuit Vd as in this embodiment, the control signal of the hold circuit H can be generated using the fluid modulation signal. Although this can be performed simply, the present invention is not limited to this point. That is, the pressure fluctuation generated due to the fluid modulation is detected, and the concentration signal output Do2 during the period in which the pressure fluctuation is occurring.
May be held.

In the above-described example, an infrared gas analyzer for measuring the concentration of carbon dioxide is exemplified as an example of a fluid modulation type gas analyzer. Needless to say, this is not a limitation. Further, the use of a gas analyzer that is susceptible to pressure fluctuations instead of the magnetic oxygen analyzer of the present invention is a readily conceivable modification.

[0018]

As described above, according to the present invention,
The noise generated in the output signal of the magnetic pressure type oxygen analyzer due to the pressure fluctuation caused by the fluid modulation can be completely removed by the hold circuit. Further, the output signal of the magnetic pressure type oxygen analyzer does not delay with respect to the output signal of the fluid modulation type gas analyzer. Further, since the circuit configuration is extremely simple, the production cost can be suppressed as much as possible while exhibiting a sufficient effect. In addition, by generating the control signal of the hold circuit using the fluid modulation signal, the oxygen analysis can be effectively performed only while the solenoid valve used for the fluid modulation operates and has an influence on the oxygen analyzer. It is very easy to hold the output of the meter and prevent the indication noise from appearing. That is, the reliability of the output signal can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a gas analysis system according to the present invention.

FIG. 2 is a time chart showing changes in signals of various parts of the gas analysis system.

FIG. 3 is a block diagram showing a configuration of a conventional gas analysis system.

[Explanation of symbols]

1 ... gas analysis system, D ₁ ... fluid modulation method of the gas analyzer, D ₂ ... magnetic pressure oxygen analyzer, Do2 ... output signal, D
o ': output signal after processing, H: hold circuit, N: noise, Vd3: hold signal.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G053 AA01 AB18 BA06 BB01 BB20 CA13 CB09 CB21 DB05 2G059 AA01 BB01 CC04 CC07 EE01 FF10 HH01 MM11 MM17 NN04

Claims (2)

[Claims] In a gas analysis system capable of analyzing a plurality of component gases by combining a magnetic pressure type oxygen analyzer with a fluid modulation type gas analyzer, an output signal of the oxygen analyzer is held in accordance with the timing of fluid modulation. And a concentration signal processing circuit having a hold circuit for cutting noise contained in the output signal is provided on the output side of the oxygen analyzer. 2. The gas analysis system according to claim 1, wherein a control signal of the hold circuit is generated using a fluid modulation signal.